Pump



Aug- 30, 1966 G. scHWl-:D ETAL 3,269,325

INVENTORS George Schwed Richard D. Combs BY y@ ATTOR EY1 Aug- 30, 1966G. scHwr-:D ETAL. 3,269,325

PUMP

Filed July 29, 1963 2 Sheets-Sheet 2 INVENTORS .N George .SchwedRic/:grd D. Combs BY TM/? m RNEYS United States Patent O 3,269,325 PUMPGeorge Schwed and Richard D. Combs, Sacramento, Calif., assignors toArthur G. McKee & Company, Cleveland, Ohio, a corporation of DelawareFiled July 29, 1963, Ser. No. 298,039 11 Claims. (Cl. 10S- 103) Thisinvention .relates to improvements in a self-priming non-clogging pump.Self-priming pumps are genertally described as those that will free-themselves of air when they become air bound and will resume pumpingaction without attention.

Standard centrifugal pumps can be installed with pressure controls,vacuum pumps, float operated separating tanks and various other controlsdesigned to keep the pumps primed, but these devices are expensive,cumbersome, complicated land not altogether reliable.

Pumps with auxiliary controls cannot properly be called self-primingpumps, because the pumps themselves do not do the priming.

In order to free :a centrifugal pump of air and make it self-primingwithout shutting it down, it is necessary to mix liquid from someoutside source with the lair that lis binding the pump. Here is thebasic method that is used:

Liquid from a reservoir on the discharge side of the pump impeller isallowed to splash on the impeller; the liquid picks up the air in theform of bubbles and removes it from the suction side of the pump.

There are many methods now in use by which centrifugal pumps tare madeself-priming. However, tal-l these methods can be reduced .to twofundament-al types, each employing 4a different principle, one of whichmay be called Recirculation Priming and the other Diffuser Priming.

Both methods require that the pump be illed with liquid before it is rststarted.

Then, when the pump is started, the liquid travels through the pump,converting it temporarily into 'a wetvacuum pump and exhausting the tairfrom the suction line.

Generally, the upper part of the pump Iis made as -a tank through whichthe discharge of the impeller passes to the discharge pipe, and thistank assures 'a lreservoir of liquid ready for priming at al-l times.

In Recirculation Priming, of which the structures illustrated in U.S.Patents No. 1,824,465 of September 22, 1931 to Carter and No. 2,755,743of July 24, 1956 to H. E. Rupp are illustrative, a connection betweenthe reservoir an-d the suction side lof the pump provides la passagewayfor the priming liquid. To prevent constant recirculation when the pumpis primed tand working, a means of shutting off the by-passed liquid isusually provided. This control may be actuated manually, by the tank andthe suction pipe.

The above kind of pump operates in this Way: When air enters the suctionline and the prime is lost, the bypass control valve drops down, due toits own weight, and recirculation commences immediately. When the pumpis pumping, the force of the stream is sucient to hold the valve closed,thus cutting off recirculation.

Recirculation-type self-priming centrifugals are used both widely andsuccessfully, but they are deficient in certain respects. If `anythingbut clear, clean uids are pumped, by-pass valves and ports are likely tobecome clogged or jammed. Furthermore, it of course takes energy tooperate the priming devices, and this means a waste of power `and adecrease in operating efficiency, compared to a diffuser-priming pump.

impeller-tank recirculation pumps, illustrated by Patent 2,002,454utilize a large rectangular-shape tank adjacent a flow-through impellerto exhaust entrapped air by .recirculating liquid between the tank andthe impeller without requirement of additional recirculation structure.Such tank type recirculation self-priming pumps are of `only limitedso-lids-carrying liquid displacement application since the solidsentrained in the liquid cause excessive wear to the flow-throughimpeller, are easily clogged in the impeller vanes, and frequently tendto occulate the solids whereby the dimensions thereof are increasedresulting in an increased likelihood of discharge clogging. Furthermore,the suction lift and the discharge head characteristics of this typepump assembly render it inapplicable for many pumping uses. The tank,due to its shape .and location, causes undesirable liquid flow currentswhich result in fluid settlement due to redundant flow and inherentlyproduce eddy currents Within the tank tending to cause the solids toflocculate often to dimensions greater than the discharge outletdimensions so as to result in clogging. Additionally, the tank mustremain substantially full of liquid during inactivity in order thatselfpriming may be undertaken, making check valves essential to preservethe entire volume of liquid in the tank and also necessitating frequentmaintenance and cleaning.

Diifuser priming, of which the structure shown in U.S. Patent No.2,653,546 dated September 29, 1953 to A. S. Marlow, Jr. is illustrative,is distinguished from recirculation priming by the fact that the primingliquid is not returned to the suction side of the pump, but mixes withthe .air at the circumference of the impeller. The 4ability to handleair is thus inherent in the design of the casing `and impeller, and thepump is not subject to any of the mechanica-l failures of recirculationpriming mechanisms.

A highly elcient diffuser-type pump has been perfected, wherein theimpeller with a diffuser ring has been submerged inside a casingsuiciently large to hold a reservoir of liquid which will assureself-priming under all conditions.

During the priming or repriming cycle in this pump, the reservoir liquidcirculates or drops back through the diffuser passages to the tips ofthe revolving impeller. The entire circumference of the impeller issealed by the reservoir liquid, and the liquid is repelled fromreturning to the suction by the revolving impeller vanes. During thisrepelling of the reservoir liquid by the impeller vanes, there isviolent splashing at the tips of the vanes.

This action picks up air from the impeller. The air is expelled throughthe diffuser passageways and escapes by bubbling to the surface of theliquid. Here it is eliminated from the system, while the reservoirliquid is returned to the impeller tips through the same passageways tocapture more air.

Continuously and very rapidly, this action goes on until all air iseliminated. At this time, liquid lls the suction line and pumpingbegins.

This invention relates to a method of -combining some of the features ofrecirculation priming and diffuser priming to provide a means forpriming vortex type swirl pumps of the type disclosed in U.S. Patent No.2,635,548 of April 2l, 1953 to C. H. Brawley and No. 2,958,293 to R. F.Pray, Jr.

The primary object of this invention is therefore to provide anon-clogging vortex type solids pump which is self-priming and a novelmethod of priming such pumps. Ancillary objects are provision of such apump with a priming chamber at its outlet and siphon breaking means atits inlet which priming chamber:

(a) Is connected to the pump by a single channel through whichrecirculation can take place during priming and unilateral discharge cantake place after priming,

(b) Has the minimum volume providing optimum water depth over theimpeller for maximum suction lift,

(c) Provides an unobstructed ow path through the outlet for any solidwhich can enter the pump,

(d) Precludes occulation of solids, particularly stringy solids, withinthe pump, and t (e) Precludes retention of sediment therein while thepump is shut down.

Other objects and novel features will become apparent by reference tothe appended claims and as the description proceeds in connection withthe accompanying drawings wherein:

FIGURE 1 is a side elevation to scale of one solids pump embodiment ofthis invention, illustrating a pump chamber and a priming chamberconstruction with the associated inlet and outlet ports anddiagrammatically showing the fluid dynamics of flow which occur duringthe priming stage and during fluid displacement through the pump;

FIGURE 2 is substantially a vertical cross-sectional view to scale alongline 2-2 of FIGURE 1 illustrating one construction of the presentinvention showing the relationship of the influent Siphon breakerchamber, the pump chamber with its associated offset impeller and thepriming chamber including the effluent discharge port;

FIGURE 3 is a cross-sectional view to scale along line 3-3 of FIGURE 1illustrating the nature of the cross-section of the inclined throatintermediate the pump chamber and the priming chamber;

FIGURE 4 is an elevation view to scale showing the interrelationshipbetween the inlet, the outlet, the Siphon breaker chamber, the pumpchamber, the priming chamber, the impeller and associated drivemechanism and the prime mover, in this case, an electrical motor;

FIGURE 5 is a side elevation to scale view along line 5-5 of FIGURE 4showing the location and shape of the siphon breaker chamber;

FIGURE 6 is a diagrammatical elevation View in section corresponding tothe pump arrangement of FIGURE 1 showing an inlet pipe fed by a fluidsource and illustrating in particular the relationship between theoptimum volume of solids-carrying liquid and air entrapped within thepump during the periods when the impeller is idle;

FIGURE 7 is a diagrammatical elevation View in section similar to FIGURE6, further illustrating the nature of the liquid and air displacementand discharge during self priming action; and

FIGURE 8 is an elevation view in vertical section through the pumpingchamber along line 8-8 of FIG- URE 7, illustrating the nature of thenovel recirculation liow path for exhausting the entrapped air throughthe unobstructed throat, priming Ichamber, and discharge port.

Several attempts to achieve the aforesaid primary object have been madeusing the conventional recirculating and diffuser-type self-primingdevices integrated with the vortex-type torque-flow pump. Although itwas discovered that the Vortex-type torque-flow impeller could beself-primed in this manner, in actual tests and field operation, thisparticular combination would plug up similarly to conventional typenon-clog centrifugal pumps. Various modifications were made usingstandard priming devices, but in every instance, some of the features ofself-priming devices would turn out to be an obstacle to certain solids.The reason for the failures can be attributed to the fact thatconventional self-priming devices characteristically have openings orclearances that are smaller in diameter than the size of the pipelinethat feeds or discharges the pump. The vanes in the volute, no matterwhat their dimensions, will tend to hang up long stringy particles onthe leading edges. The vanes of the volute which make possible thediffuser principle, i.e., the feature of peeling off the bubbles, appearto be necessary in a self-priming unit. Unfortunately, any type ofvolute vane serves as an obstacle and will eventually clog. In theexperiments to develop a self-priming vortex, diffuser priming wasfurther complicated by the fact that recirculation channels with theircommensurate low velocity provide a settling point for heavy solids.Free-flowing heavy solids like sand and gravel will tend to settle outand plug up recirculation channels in diiuser-type self-priming.

In one experiment, an impeller of the type disclosed in said Pray patentwas completely removed from a conventional diifuser case such as that ofsaid Marlow patent by a separator ring to make it completely recessedand out of the main flow. This design was found to be selfpriming, whichproved that a fully-recessed impeller would self-prime; however, thisdesign was not operable since the vanes of the volute employing thediffuser principle became plugged in actual eld tests. A screen at theentrance to the recirculation channels was installed to pre; vent thesolids from entering these channels. The problem here was that it becameimpossible to prevent the screens from building up and blinding.

The conclusion that can be drawn from the above experimental work isthat all conventional methods of selfpriming are not suitedl to thecharacteristics of the vortex pump principle. Any openings less than thedischarge pipe diameter were not practical. Any vanes, peelers, screens,etc. all served as obstacles and tended to clog up the unit.

To design a truly non-clog vortex type pump that would be self-priming,it appeared that it would be necessary to design a self-primer with verylarge openings and a method of permitting the reuse of priming waterduring the priming cycle,` and a method of quickly discharging theentrapped air; i.e., to deplete the supply of entrapped air in thesuction side of the unit. Also there would be the diicult problem ofproviding a means to seal off the reduced pressure in the suction linewhich would be developed during the priming cycle from the relativelyhigher pressure in the discharge side.

In all centrifugal pumps of opened or enclosed or tube type so-callednon-clogging impellers, there is a relatively close clearance or sealarea that does not compare with the vortex type pump which has a sealingarea or distance as great as the pipeline itself. Therefore, the problemof sealing the air across the discharge opening at first appeared to beinsurmountable. A unit was then de.- signed with the hope that thevortex cyclone or Whirl effect would itself act as a discharge seal andpermit the reduction of 'air in the suction side to be dissipated intothe discharge side. In an experimental test, the Torque- Fow unitoperated satisfactorily and held a differential pressure up to 11 lbs.across the sealing varea of the suction and discharge. The next problemwas the obstruction in the discharge of the volute, which was thoughtnecessary to separate the return iiow. This guide vane or separationvane appeared to be necessary to provide a recirculation channel. Thisvane was removed quite by accident to see what would happen. An unusualphenomenon took place that enabled the pump to be completelyself-priming without the special recirculation channel, thereby removingthe last obstacle to a truly self-priming vortex pump.

The general relationship of the component parts of an installed solidspump typical of the present invention is shown in FIGURE 4, havingseriatim between inlet port 10 and outlet port 12, Siphon breakerchamber 14 secured toward its lower extremity to pump chamber andimpeller housing 16, communicating throat 18, and priming and vortexdamping chamber 20, providing an unrestricted ow path forsolids-carrying liquid since no openings in the pump have a dimensionperpendicular to the direction of ow less than the minimum `dimension ofthe inlet and outlet ports. The impeller of the arrangement of FIGURE 4is driven by shaft 22 which in turn isrotatably driven 4by prime mover24. Prime mover 24, depending on the circumstances, may be any one ofseveral Vtypes of prime movers utilized to rotate the pump impeller,

for example, a direct drive electric motor or a belt driving internalcombustion engine. While siphon breaker chamber 14 is the preferred modeof preserving priming fluid in the pump, under some conditions aswinging check valve may be used in place of chamber 14 as for examplewhere available space prohibits utilization of a chamber having thedimensions of chamber 14. However, such valves are easily unseated bysolids with attendant loss of prime, a problem obviated by use ofchamber 14.

Referring to FIGURE 2, liquid displacement pumping solids-carryingliquid is drawn in at inlet 1), transmitted through chambers 14 and 16,throat 18, and chamber 243 to be discharged at outlet 12, consequentialof pressure differential created by rotation of offset impeller 15 in aunique flow pattern hereinafter to be described.

Siphon breaker 14, cantilever bolt fastened to chamber 16, includesolf-set inlet 10, abutment 26, tank portion 28, efuent portion 3i) andflange portion 32. The general shape of siphon breaker 14 is such as toprovide in a minimum of space sufficient tank volume capacity to breakthe Siphon back pressure following pump shut off and thereby retain inthe pump a predetermined volume of solids-carrying priming liquid, whichis less than the volume of the pump. The shape of chamber 14 as viewedalong the vertical plane of the axis of rotation of the impeller isshown on the right of FIGURE 2, while the rear elevation shape appearsin FIGURE 5.

For manufacturing and installation convenience a portion of pump chamber16 as well as the entirety of priming chamber 20 are integrally formed.Chamber 16 permits uid to communicate from effluent portion of chamber14 at port 34 and bolt receives impeller mechanism 15 at port 36.Impeller mechanism 15, as shown in FIGURE 2, includes shaft 22, shaftsleeve surrounding shaft 22, back plate 42 which forms a portion of thechamber 16 and lockscrew held impeller 44 which is appropriately offset`and recessed out of the path of normal flow of the solids-carryingliquid being communicated through chamber 16 thereby avoiding cloggingof the vanes and erosive wear of the impeller by the solids. Impellermechanism 15 preferably includes the detailed structure and functions ina manner defined in Patent No. 2,635,548 to which reference may be madefor greater detail. All passages along the liquid flow path from inlet10 through outlet 12 are constructed so that there are no constrictionstherein which are of lesser size than that of the maximum size particlewhich can enter the pump to thereby preclude internal clogging.

Priming and vortex damping chamber 20 uniquely includes unobstructedventuri-like throat section 18, which as shown in FIGURE 1 along line 33, is inclined preferably on the order of 20 to 30, with respect to thevertical to avoid solids accumulation during pump inactivity and isoffset with respect to the center of both chambers 16 and 20 tofacilitate the unique flow pattern yet to be described. Outlet port 12is located at the upper portion of chamber 20, which also includes aanormally closed access port 44 and abutment 46 engaging abutment 26 ofchamber 14. To increase structural integrity with respect to chambers 14and 20, nut and bolt assemblies 48 (FIGURE 4) secure chamber 14 tochamber 20 by means of bosses 50 and 52.

The optimum shape of priming chamber 20, arrived at through empiricalstudies, forms a major part of the present invention. The internalconfiguration of chamber 20 provides a maximum rate of priming fluidrecirculation between the priming chamber 20 and the pump chamber 16during priming but none after full flow is established consistent withmaximum suction lift, optimum water depth over the impeller for priminga flow path for solids along the interior surface which is free of eddycurrent producing housing configurations and internal surfaces allsloped with respect to the horizontal preferably at an angle slightlygreater than the angle of repose of the various products to be pumped,to preclude collection of solids within the priming chamber duringshutdown of pumping.

Extensive tests revealed that for the requisite suction lift anddischarge pressure, at least for small diameter impeller pumps, theratio lof the initial depth of priming `liquid above the centerline ofthe impeller with respect to the impeller diameter, hereinafter calledthe depthdiameter ratio, has a minimum practical value on the order of1.33, otherwise adequate priming action cannot be obtained. Maximumsuction lifts .were obtained when the depth-diameter ratio was in theorder of 2.88. Suction lifts of 28.3 feet of water were provided by thepresent invention when the depth-diameter ratio was on the order of 2.2times the impeller diameter.

Depth alone, however, is not the only influencing factor. Relativevolumes, it was discovered, may be determinative with respect to themagnitude of suction lift obtainable. When the ratio iof the yvolume ofthe priming water stored in the priming chamber 20 during pumpinactivity with respect to the volume of the pump chamber, hereinaftercalled the vol-ume ratio, was on the order `of 6 maximum suction liftwas obtained. Larger volume ratios were found to decrease the magnitudeof the suction lift. Suction lifts in excess of 28.3 feet of water wereprovided when the volume ratio was substantially 2.6.

It should be noted that not only does chamber 20 gently taper away fromthroat 18 in diverging-converging fashion, bu-t the center of chamber 20is asymmetrical being horizontally loff-set both with respect to thecenter of chamber 16 and the center of throat 18 as viewed in FIGURE 1.

As seen in FIGURE 2, however, chamber 20 is symmetrical about itsvertical centerline, permitting maximum required suction lifts andmaximum discharge pressure to be obtained. This shape enables entrappedair to be exhausted during the priming stage and, under all conditions,solids carried in the liquid are retained in suspension so as to obviatesettlement, ilocculation and clogging thereof. No close clearances arerequired lto be maintained and solids do not have to pass through anyimpeller ports yor passages nor thro-ugh any separate recirculationchannels, diffusers or other obstructions which would tend to clog thepump.

Commercially, both four inch and three inch torque ow self-primingnon-clogging solids pumps of the present invention have Ibeen developedwith capacities for the four inch model ranging from 50 g.p.m. to 500gpm. and including shut-off head at 1800 r.p.m. of approximately feet ofwater.

In operation, as illustrated in FIGURE 6, assuming the pump to containample priming liquid and to be attached to a solids-carrying liquidsource 54 through inlet pipe 56, prime mover 24 (FIGURE 4) is poweractuated .so as -to rotate shaft 22 which in turn drives impeller 44(FIGURE 2). The rotation of impeller 44 creates hollow vertical -uidflow in the direction of rotation of the impeller within the pumpchamber 16, driving the solidscarrying liquid rotatably along theperiphery of the chamber 16, out through a por-tion of throat 18 (FIG-URE 3), recirculating through chamber 20 into a gentle loop flow path ina direction opposite to the rotation of the impeller 44, and back intochamber 16 through the remaining portion of throat 18. The particularrelationship of chambers 16 and 20 and throat 18 permits rapidrecirculation and countercurrent flow through throat 18 withoutoc-culation or settlement of solids.

As the above described recirculation takes place, the water level in thepriming chamber 20 immediately rises as the siphon breaker chamber ispumped dry of liquid. The swirling motion created `in pump chamber 16 byrecessed impeller 44 continues as liquid is suspended in priming chamber20, and as liquid is recirculated by pressure gradient created in throat18 by the swirling action in chamber 18 of the impeller as above stated.Consequently, the ywater ylevel in inlet tube 56, as shown in FIGURE 7,will rise progressively from the initial position shown rin FIGURE 6 atthe level of source 54 to the position shown in FIGURE 7. Before pumpingcan be established, the entrapped air in the Siphon breaker chamber andthe connecting pipe must be eliminated. This entrapped air `in the inletand chamber 14 will be drawn into the vortical flow 57 (FIGURES 1 and 8)being created in chamber 16 so as to be violently corningled with thesolids-carrying .liquid to pass therewith through throat 1S into chamber20 along a por-tion of flow loop 58 where the air, being lighter thanthe liquid, is gravimetrically exhausted from the liquid throughdischarge 12 as seen at 60 of FIGURE 8. Wheretrpon, after exhausting ofthe air, the solids-carrying liquid without settlement of flocculationof the solids returns to the outer edge of impeller 44 in chamber 16along flow path 61 in the direction of rotation of the impeller.

In actual operation, the exhaust of such entrapped air is characterizedby a rapid pulsing motion in the priming chamber with intervals on thelorder of one second between pulses. The surface of the water in thepriming chamber is constantly disturbed by the action of the air beingreleased. As the partial lvacuum being created at the intake of the pumpincreases, the pulsing action gradually becomes more frequent andviolent until the pump becomes partially primed. At this point thepulsing action rapidly dies out as the pump completely exhausts theremaining air in siphon breaker chamber 14 so at full capacity owthrough the priming chamber is essentially laminar with only immaterialturbulence apparent at the corners of the priming chamber. In actualtests, vacuum guage readings in excess of 30.6 of water at the pumpsuction have been obtained. The recirculation pattern of the liquid flowduring priming allows the liquid t-o be re-used to trap additional airduring the priming cycle and thus the volume of water required to primeis constant irrespective of the length or diameter of the suction intakepipe.

Once the pump has been primed the flow path of the liquid passingthrough chamber 16 and 20 is indicated by flow arrows S5, 57, and 62. inFIGURE 1, chamber 20 being so internally contoured as to damp eddycurrent action at its incipiency to preserve laminar ow, preventsettlement and accumulation of solids in the chamber, and obviateflocculation of the solids which would result govortical flow were toexist at the surfaces of chamber The invention may be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. The present embodiment is therefore to beconsidered in all respects as illustrative and not restrictive, thescope of the invention being indicated by the appended claims ratherthan by the foregoing description, and all changes which come within themeaning and range of equivalency of the claims are therefore intended tobe embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. A self-priming, non-clogging solids pump comprising fluid guidestructure dening seriatim an inlet, a siphon breaker chamber below saidinlet, a pump chamber below said inlet to receive the effluent from saidSiphon breaker chamber, a priming cham-ber located above and forming anextension of said pump chamber and an outlet at the upper portion ofsaid priming chamber; a rotatable impeller mounted on the said guidestructure at said pump chamber and located substantially completelyoutside of the main path of uid flow therethrough and operative whenrotated to create vortical uid flow in said pump chamber to induce fluidflow from said Siphon breaker chamber through said pump chamber intosaid priming chamber, said chambers and the passages between saidchambers being unobstructed and the passage between the pump and primingchambers forming a throat of such size and shape that any solid whichmay pass through said inlet can pass through said throat into saidpriming chamber so that passage between said inlet and outlet of solidparticles entrained in fluid passing therethrough is not precluded, theinternal cross-section of said priming chamber as viewed in a planeperpendicular to the vaxis of rotation of the impeller being essentiallyof diverging-converging form from the throat connecting the pump chamberand the priming chamber to the outlet and wherein the centerline throughthe throat is inclined substantially from the vertical and wherein thewalls of said pumping chamber smoothly merge with the walls of saidpriming chamber through said throat.

2. The solids pump defined in claim 1 wherein said throat centerline isinclined from the vertical on the order of 20 to 30.

3. The solids pump defined in claim 1 wherein the center of the primingchamber as viewed in cross-section perpendicular to the axis of rotationof the impeller is off-set from a vertical plane passing through theaxis of the impeller in the direction of the horizontal component offluid flow of the priming chamber inuent.

4. The pump dened in claim 3 wherein said inclination of said throatwith respect to the horizontal in a plane perpendicular to the axis ofrotation of the impeller is anti-clockwise as viewed from the bladedside of the impeller and wherein the center of the priming chamber issimilarly offset as so viewed from a Vertical centerline through theimpeller axis of rotation, when intended rotati-on of impeller isanticlockwise when so viewed.

5. A self priming non-clogging solids pump for conveying solids-carryingliquid defined in seriatim by an inlet adapted to receive saidsolids-carrying lluid from its source, a siphon breaking chamberattached to but below said inlet for breaking the siphon back pressurewhen said pump becomes inactive to permit storage of priming liquid insaid pump, a vortically shaped pump chamber having an axial inletopening and circumferential outlet opening and situated below said inletto receive the effluent from said Siphon breaking chamber, a primingchamber above said pump chamber and an outlet port at the upper portionof said priming chamber, a rotatable impeller recessedly located withinsaid pump chamber adjacent the path of liquid flow to produce vorticalflow in said pump chamber to thereby induce fluid flow in a vorticalpath from said inlet opening to said outlet opening without materialcontact of any entrained solids with said impeller, said pump chamber,said siphon breaker chamber and said priming chamber Ihavingcross-sectional dimensions all of which are at least equal to theminimum cross-sectional dimension of said inlet whereby internalclogging of said pump is precluded, the ratio of the volume of saidpriming chamber with respect to the volume of said pump chamber beingbetween 2.6 and 6.0 and the ratio between the depth of priming liquidabove the centerline of the irnpeller contained within the siphonbreaker, the pump and the priming chambers during inactivity withrespectto the impeller diameter is between 1.3 and 2.9 whereby self priming andmaximum suction lift characteristics may 'be selectively obtained; thecontour of said internal surfaces -of the priming chamber comprising aseries of curves `defined such that the lines normal to tangent linesthereof intersect each other at independent positions wherebyflocculation of said solids is prohibited thereby preventing increase inthe dimensions of said solids, the junction between said priming chamberand said pump chamber forming an unobstructed throat inclined on theorder of 20 to 30 with respect to vertical whereby during primingentrapped air is aerated through said solids-carrying liquid along onesegment of said throat in one direction and the solids-carrying liquidabsent the air is returned to the pump chamber in the opposite directionalong the remaining portion of said throat whereby both solidssettlement and occulation is obviated, said priming chamber beingsubstantially symmetrical as viewed in vertical cross-section along aplane including the axis of rotation of said impeller and asymmetricalas viewed in vertical cross-section along a plane perpendicular yto saidlast mentioned plane.

6. A self-priming non-clogging solids pump comprising:

(a) fluid guide structure defining seriatim:

(al) an inlet;

(a2) a first chamber;

(a3) a pump chamber having axially spaced walls, an inlet throat throughone of said walls and through which said pump chamber is connected toreceive the effluent from said first chamber and an annular recessedimpeller chamber in the other of said axially spaced walls;

(a4) a priming chamber located above said pump chamber, connected influid communication therewith by said pump chamber outlet throat and(a5) an outlet at the upper portion of said priming chamber sufficientlylarge to permit discharge of any solid passing through said pumpchamber;

(a6) said fluid guide structure being effective upon termination of pumpoperation and during self-priming operation to trap and maintain asufficient volume of liquid therein to maintain a liquid seal -betweensaid pump chamber inlet throat and said outlet while said pump isinoperative and during priming;

(b) a rotary open faced impeller disposed in said impeller chamber ofsaid pump chamber, said impeller having a plurality `of blades forcausing movement `toward the end portion of each of said blades of theportion of fluid in said chamber adjacent said blades, said bladessubstantially facing the portion of said pump chamber between saidwalls, the portion of said impeller facing said chamber being laterallyspaced from the portion of said chamber disposed opposite thereto toform a lateral clearance extending between all of said portion of saidirnpeller and said chamber to form an unobstructed passage between saidpump chamber inlet throat and the `outlet throat which passageconstitutes the primary path of fluid flow between said throats;

(c) said pump chamber outlet throat being disposed at the periphery ofsaid lateral clearance and being at least substantially coextensive inwidth therewith, said outlet throat diverging into said priming chamberfrom its region of minimum cross section and beyond said region ofminimum cross section being at least as large as said region of minimumcross section so that any object passing through said region of minimumcross section will pass into said priming chamber and out said outlet;

(d) whereby, during priming of said pump at least the major portion ofthe liquid returns into said pump chamber through said pump chamberoutlet throat and enters said lateral clearance directly and flowstoward the bottom of said pump chamber in a path axially offset from thepath of rotation of said impeller blades to entrap air in said pumpchamber for redischarge into said priming chamber when said liquid againcomes under the influence of the fluid flow created by said impellerwhereby said self-prim- `10 ing non-clogging solids pump is operative toevacuate entrapped air and thereby self prime through repetition at aprogressively increasing .rate until the pump becomes partially primedof the following steps:

(l) commingling the air to be exhausted with liquid in said pumpchamber,

(2) discharging the air and liquid from said pump chamber into saidpriming chamber through said pump chamber outlet throat,

(3) gravitationally separating said air from Said liquid in said primingchamber for discharge through said outlet, and

(4) returning at least the major portion of the liquid from said primingchamber into said pump chamber through said pump chamber outlet throatin a path axially offset from the portion of rotation of the blades ofsaid impeller.

7. The solid pump defined in claim 6 wherein the volume of said primingchamber below. said outlet is at least equal to the volume of liquidtrapped in the bottom of said first, said priming and said pump chamberswhen the level thereof above the center line of the impeller is at least1.3 times the impeller diameter while the impeller is at rest followingloss of suction.

8. The solids pump defined in claim 6 wherein the ratio of the volume ofthe said priming chamber to the volume of said pump chamber is at leastequal to 2.6.

9. The solids pump defined in claim 6 wherein the ratio of the volume ofsaid priming chamber to the volume of said pump chamber is in the orderof 6.

10. The solids pump defined in claim 6 wherein the angle of inclinationfrom the horizonal of all upwardly facing internal surfaces of thepriming chamber is sufficiently greater than the angle of repose of thesolids to be pumped therethrough to prevent any material accumulation offinely divided solid particles thereon during periods which the pump isshut down.

11. The pump defined in claim 6 wherein the internal curved surfaces ofsaid priming chamber essentially along the path of fluid flow thereinare non-circular whereby vortices formed in said chamber are damped attheir incipiency thus preventing fiocculation of said solids.-

References Cited by the Examiner UNITED STATES PATENTS 2,166,358 7/1939La Bour 103-113 2,635,548 4/1953 Brawley 103-103 2,635,549 4/1953 Rupp103-103 2,958,293 11/1960 Pray 103-103 3,130,679 4/1964 Sence 103-1033,171,357 3/1965 Egger 103--87 FOREIGN PATENTS 525,512 5/1956 Canada.

660,807 4/1963 Canada.

673,662 3/1939 Germany.

574,079 12/ 1945 Great Britain.

849,449 9/ 1960 Great Britain.

44,413 6/ 193 8 The Netherlands.

MARK NEWMAN, Primary Examiner.

JOSEPH H. BRANSON, JR., HENRY F. RADUAZO,I

KARL J. ALBRECHT, Examiners.

1. A SELF-PRIMING, NON-CLOGGING SOLIDS PUMP COMPRISING FLUID GUIDESTRUCTURE DEFINING SERIATIM AN INLET, A SIPHON BREAKER CHAMBER BELOWSAID INLET, A PUMP CHAMBER BELOW SAID INLET TO RECEIVE THE EFFLUENT FROMSAID SIPHON BREAKER CHAMBER, A PRIMING CHAMBER LOCATED ABOVE AND FORMINGAN EXTENSION OF SAID PUMP CHAMBER AND AN OUTLET AT THE UPPER PORTION OFSAID PRIMING CHAMBER; A ROTATABLE IMPELLER MOUNTED ON THE SAID GUIDESTRUCTURE AT SAID PUMP CHAMBER AND LOCATED SUBSTANTIALLY COMPLETELYOUTSIDE OF THE MAIN PATH OF FLUID FLOW THERETHROUGH AND OPERATIVE WHENROTATED TO CREATE VORTICAL FLUID FLOW IN SAID PUMP CHAMBER TO INDUCEFLUID FLOW FROM SAID SIPHON BREAKER CHAMBER THROUGH SAID PUMP CHAMBERINTO SAID PRIMING CHAMBER, SAID CHMABERS AND THE PASSAGES BETWEEN SAIDCHAMBERS BEING UNOBSTRUCTED AND THE PASSAGE BETWEEN THE PUMP AND PRIMINGCHAMBERS FORMING A THROAT OF SUCH SIZE AND SHAPE THAT ANY SOLID WHICHMAY PASS THROUGH SAID INLET CAN PASS THROUGH SAID THROAT INTO SAIDPRIMING CHAMBER SO THAT PASSAGE BETWEEN SAID INLET AND OUTLET OF SOLIDPARTICLES ENTRAINED IN FLUID PASSING THERETHROUGH IS NOT PRECLUDED, THEINTERNAL CROSS-SECTION OF SAID PRIMING CHAMBER AS VIEWED IN A PLANEPERPENDICULAR TO THE AXIS OF ROTATION OF THE IMPELLER BEING ESSENTIALLYOF DIVERGING-CONVERGING FORM FROM THE THROAT